1. Field of the Invention
The present invention relates generally to hearing aids. More specifically, it relates to an elbow shaped device which connects earmold tubing from a hearing aid to an earmold and which enhances high frequency response within the elbow.
2. Description of the Prior Art
A conventional hearing aid apparatus is comprised of the actual hearing aid having a sound exit port, to which flexible plastic sound conduction tubing is attached. Such tubing is permanently attached to a sound input port in an earmold. The earmold is disposed in the ear of the wearer. Sound travels from the hearing aid, through the tubing, and through a bore in the earmold directly into the user's ear canal. In such a design, tubing replacement is difficult and costly.
An elbow shaped means for connecting the sound conduction tubing to the earmold is known in the art. For example, Jelonek et al. (U.S. Pat. No. 4,381,830) discloses an elbow connector designed to provide a sound conducting bore of constant internal diameter between the sound conduction tubing attached to a hearing aid and the sound conduction bore of the earmold. As such, a continuous flow sound conduction path is established from the hearing aid through the earmold into the ear canal. The end of the sound conduction tubing may be spaced from a shoulder within the sound conduction bore of the connector thereby forming a resonance chamber to increase the strength of high frequency signals.
An increase in the diameter of the sound conduction tubing at the point nearest the earmold is also known in the art. This increase has been accomplished in two ways. Two sections of sound conduction tubing with different diameters are cemented together via a difficult and time consuming process. Alternatively, a single sound conduction tube with an internal step-up in diameter may be molded. However, Applicant has learned that molding tubing with an internal increase in diameter is prohibitively expensive. In addition, the molding process weakens the tubing, making it less durable. Therefore, replacement of the sound conduction tubing is required frequently and at significant expense. In either of the above described methods for increasing the diameter of the tubing, the tubing end is cemented into the earmold, making replacement of the tubing sections inconvenient.
Johnson (U.S. Pat. No. 4,311,206) discloses an abrupt change in diameter of the sound conduction passage from constant diameter tubing to a bore of increased volume within the earmold. The interior chamber of the earmold is drilled to various geometric shapes and volumes to define a particular acoustic resonating system. To accomplish this method of increasing high frequency response, the earmold is split into two sections, a cavity of desired volume is drilled, and the earmold is cemented back together. An earmold thus produced is costly.
Accordingly, the need exists for a connector which facilitates easy replacement of sound conduction tubing while providing a means for improving high frequency response.